Liquid compounds liable to exothermic decomposition decompose above certain critical temperatures to produce gas and heat. The heat produced further promotes the decomposition. Such compounds, and solutions, dilutions, suspensions, and emulsions containing such compounds, are thus referred to as "self-heating" or "exothermically decomposing compounds." Examples of such compounds are liquid organic peroxides with explosive properties, such as tert.-butyl perxoybenzoate, tert.-butyl peroxypivalate (up to 77% in solution), tert.-butyl peroxy-2-ethylhexanoate and tert.-butyl peroxy isopropylcarbonate (up to 77% in solution); other organic peroxides, such as 2,5-dimethyl 2,5 ditert.-butyl peroxyhexane, tert.-butyl peroxy acetate (up to 52% in solution), di(3,5,5trimethyl hexanoyl) peroxide (not more than 77% in solution), and methyl ethyl ketone peroxides (not more than 40% in diisobutyl nylonate); inorganic peroxides, such as hydrogen peroxide, ammonium peroxydisulphate, alkaliperborates. alkalipercarbonates, ammonium peroxymonosulphate, alkaline earth peroxyborates, and alkaline earth persulphates; azo compounds, such as 2,2'-azo di-(2,4-dimethyl)valeronitrile 50% in methylethylketone; nitrate compounds, such as 2-ethyl-hexylnitrate; nitrile compounds, such as pentylnitrite; and sulphohydrazides, such as benzenesulphohydrazide, N-nitroso compounds, nitro compounds and organic nitrates.
The storage and transportation of exothermic decomposition compounds are particularly troublesome in that the build-up of decomposition gases in the transportation or storage container may cause violent, hazardous explosions, bursting the container holding the compounds. In recognition of this problem, international safety laws and standards regulate the size and construction of containers used to store and transport such compounds. For example, the standards of the UN publication "Recommendations on the Transport of Dangerous Goods" limit the transportation of certain liquid organic peroxides to 50 kg plastic containers. International regulations for the transportation of organic peroxides are also contained in the "European Agreement Concerning the International Carriage of Dangerous Goods by Road" (ADR) and the "International Code for the Transport of Dangerous Goods by Ship" (IMDG-code).
These and other limitations on container design and compound concentration hamper the efficient storage and transportation of compounds liable to exothermic decomposition. The paper "Safety Aspects of Organic Peroxides in Bulk Tanks" by Jan J. de Groot, Dick M. Groothuizen and Jaap Verhoeff, "I & EC Process Design and Development", 1981, Vol. 20, pp. 131-138 (referred to as "Safety Aspects") discusses a tank designed for the bulk handling of diluted organic peroxides. The bulk storage tank in "Safety Aspects" is provided with a carbon rupture disk on top of the tank. During an accident in which the dilute organic peroxides explode, the rupture disk allows venting of the decomposition gases (and entrained liquid) to prevent bursting of the tank.
In U.S. Pat. No. 3,945,941, polyolefin particles, traps and/or liners are added to containers holding a mixture of 70% tertiary butyl hydroperoxide (TBHP) and 30% water. The polyolefin additives were found to inhibit rapid combustion of the TBHP mixture.
In Canadian Patent No. 1,148,334, disintegration or explosion barriers containing fillers such as "Pall" rings are used in processes for the distilling of ethylene oxide.
German Patent No. 149,086 discloses a container for holding hazardous liquids, such as petroleum and gasoline, which container is provided with a conduit having an inlet positioned near the bottom of the container. In case of a fire the liquid present in the container is pressed through said conduit into a closed overflow container which is provided at its top with a safety valve to allow for the escape of pressurized gases.
Currently available methods do not meet the needs of industry to safely store and transport bulk volumes of concentrated compounds liable to exothermic decomposition. Indeed, with currently available designs, decomposition and the resulting explosion and/or container rupture occur too quickly to safely reduce pressure by gas release and prevent explosion. Surprisingly, in view of the long felt need in the art, the container of the present invention provides pressure release which avoids explosion in the container.
The present invention relates to a container of the type indicated above and is characterized in that the conduit inlet is at or near the bottom of the container. Pressure inside such container is generated by the decomposition of liquid compounds liable to exothermic decomposition. When the pressure in the container reaches a certain predetermined pressure, the liquid release system is operated by the pressure in the container to discharge substantially all the liquid compound. By quickly releasing substantially all liquid from the container, explosion is avoided. The "predetermined, pressure" must be less than the maximum pressure rating of the container in order to maintain the structural integrity of the container. Generally, the maximum pressure rating of most industrial containers built for storage and/or transportation purposes is about 5 or 6 bars. However, containers having higher or lower maximum pressure ratings are not uncommon.